Themed Section: Science and Technology Design and Analysis

IJSRST173166 | Received: 15 Feb-2017 | Accepted : 27 Feb-2017 | January-February-2017 [(3)1: 408-417 ]

© 2017 IJSRST | Volume 3 | Issue 1 | Print ISSN: 2395-6011 | Online ISSN: 2395-602X Themed Section: Science and Technology

408

Design and Analysis of Various Shapes of Flywheel

Wasim Akram, Vaibhav H. Bankar

Department of Mechanical Engineering, VIT Nagpur, Maharashtra, India

ABSTRACT

In present investigation, to counter the requirement of smoothing out the large oscillations in velocity during a cycle

of a mechanism, a flywheel is designed, optimized and analyzed. By using optimization approach to optimize

various parameters like cost, stresses, energy etc. for flywheel and to apply an approach for modification of various

working parameter like efficiency, output, energy storing capacity, the results compared with existing flywheel

result. Based on the dynamic functions and specifications, of the system the main features of the flywheel is

initially determined, the detail design study of flywheel is done and by using any one of the optimization techniques

and approach for modification, structural analysis is done.

Heavy wheel attached to a rotating shaft to smooth out delivery of power from a motor to a machine. The inertia of

the flywheel opposes and moderates fluctuations in the speed of the engine and stores the excess energy for

intermittent use. In automobile engines, the flywheel smooths out the pulses of energy provided by the combustion

in the cylinders and provides energy for the compression stroke of the pistons. In power presses the actual punching,

shearing, and forming are done in a fraction of the operating cycle. During the longer, non-active period, the speed

of the flywheel is built up slowly by a comparatively low-powered motor. When the press is operating, most of the

required energy is provided by the flywheel, heavy metal wheel attached to a drive shaft, having most of its weight

concentrated at the circumference. Such a wheel resists changes in speed and helps steady the rotation of the shaft

where a power source such as a piston engine exerts an uneven torque on the shaft or where the load is intermittent,

as in piston pumps or punches. By slowly increasing the speed of a flywheel a small motor can store up energy that,

if released in a short time, enables the motor to perform a function for which it is ordinarily too small.

The flywheel was developed by James Watt in his work on the steam engine. The difficulty of casting stress-free

spoked flywheels leads the modern designer to use solid web castings or welded structural steel assemblies. For

large, slow-turning flywheels on heavy duty diesel engines or large mechanical presses, cast-spoked flywheels of

two-piece design are standard.

New optimization problems arise every day - for instance, what is the quickest path to work? Where and how

congested is the road construction? Am I better off riding my bike? If so, what is the shortest path? Sometimes these

problems are easily solved, but many engineering problems cannot be handled satisfactorily using traditional

optimization methods. Engineering involves a wide class of problems and optimization approaches.

For the machine acting a variable motion, its equivalent drive moment does not always equal to the equivalent

resistant moment even during the stable status. Since its equivalent inertia of moment cannot vary correspondingly

to this change, the angular velocity of its equivalent component, generally the main shaft or crank, fluctuate

periodically.

Serving as a reservoir by storing energy during the period when the supply of energy is more than the requirement

and releasing it during the period when the requirement of the energy is more than the supply, a flywheel provides

an effective way to smooth out the fluctuation of speed. The efficient flywheel design should maximize the inertia of

moment for minimum material used, and guarantee high reliability and long lifetime .Under such a situation and

being aimed at partial mechanism system, the project is presented and worked out on the platform of PRO-E and

ANSYS.

Keywords : ANSYS, PRO-E, Flywheel, FEA

http://www.answers.com/topic/spoke

International Journal of Scientific Research in Science and Technology (www.ijsrst.com)

408

I. INTRODUCTION

In this chapter, basic introduction of flywheel, their role

in machines to get desired outputs like moment of

inertia, energy fluctuations, torque, etc.., with respect to

corresponding inputs will explained. Based on the

dynamic functions, specifications of the system the main

features of the flywheel is initially determined, the detail

design study of flywheel is done .Then more and more

designs in diverse areas of engineering are being

analyzed through the software. FEA provides the ability

to analyze the stresses and displacements of a part or

assembly, as well as the reaction forces to other

elements are imposed. This thesis guides the path

through flywheel design and analysis to the material

selection process. The FEA model is described to

achieve a better understanding of the mesh type, mesh

size and boundary conditions applied to complete an

effective FEA model. At last the design objective could

be simply to minimize cost of flywheel by reducing

material or control the fluctuations of flywheel.

II. METHODS AND MATERIAL

Formulation of Problem : After exhaustive literature

survey from previous chapter it is to be concluded that in

today’s world, major objectives of flywheel designers

are to achieve the performance with lowest possible

material used. Many researchers have focused on the

finite element method and optimum design of flywheel,

clutch plate and other parts of the engine like connecting

rod. So, on the basis of above literature, the object of

this work is to control the fluctuations of the flywheel to

get the required inertia of the flywheel with safe

working stresses. The flywheels are of two types 1) Web

type and 2) Arm type

In older days, the flywheels were overdesigned in which

the moment of inertia of the flywheel was more. But in

modern days the attention imposes on optimal design.

The optimal flywheel design will be a flywheel having

minimum weight, to provide a particular moment of

inertia and to control the fluctuating energy with safe

stresses in all parts of the flywheel.

The present work is an attempt to optimize the existing

flywheel of Fischer punching machine (German

manufactured). The stress analysis by F.E.M method

will be done to solve the purpose. In FEM analysis,3D

model of flywheel will be developed in PRO-E and

stress analysis will be done using ANSYS software.

FORMULATION OF PROBLEM : After exhaustive

literature survey from previous chapter it is to be

concluded that in today’s world, major objectives of

flywheel designers are to achieve the performance with

lowest possible material used. Many researchers have

focused on the finite element method and optimum

design of flywheel, clutch plate and other parts of the

engine like connecting rod. So, on the basis of above

literature, the object of this work is to control the

fluctuations of the flywheel to get the required inertia of

the flywheel with safe working stresses. The flywheels

are of two types 1) Web type and 2) Arm type

In older days, the flywheels were overdesigned in which

the moment of inertia of the flywheel was more. But in

modern days the attention imposes on optimal design.

The optimal flywheel design will be a flywheel having

minimum weight, to provide a particular moment of

inertia and to control the fluctuating energy with safe

stresses in all parts of the flywheel.

The present work is an attempt to optimize the existing

flywheel of Fischer punching machine (German

manufactured). The stress analysis by F.E.M method

will be done to solve the purpose. In FEM analysis,3D

model of flywheel will be developed in PRO-E and

stress analysis will be done using ANSYS software. The

specification of punching machine and the flywheel

dimensions are as,

SPECIFICATION OF PUNCHING MACHINE:

Speed=1440rpm

Power =13.5HP

Capacity (at normal working pressure) = 100tons

Capacity (at max. pressure) = 125tons

SPECIFICATION OF FLYWHEEL:

Design parameters Of Flywheel:

Mass of flywheel=500kg

Material of flywheel=Mild Steel

Outer dia. Of flywheel=25inch = 612.5mm

Inner dia. Of flywheel = 3.5inch.= 85.75mm

Width of flywheel = 6.5inch.= 159.25mm


409

GERMAN FISCHER PUNCHING PRESS

This press is used for expanding the metal. Asian streck

metals ISO 9001:2008 Company cut die, slit and stretch

a metal sheet upto 5mm thick with no welded joints to

make a one piece heavy-duty grating (mesh).

Structural Analysis of Flywheel :-

Solid model

The flywheel of German Fischer Punching Press is of

solid disc type heavy flywheel used to store the energy

for punching operation.

Calculation of If

By a simple and easy method, in which Ir is regarded as

a constant, the required If can be calculated as fallows,

ω=2πN/60=2πx1440/60=150 rad/sec

V=ω x r = 150 x 42.875x10-3

= 6.431m/sec

a = v2 /r = 6.431

2 /(42.875x10

-3 ) = 964.68m/sec

2

Drive Force,

Fd = m x a = 500 x 964.68 = 482.34 KN

Specific weight density, W = (r/4) x 482.34 =

42.875x10-3

x 482.34/4

= 5.17KN-m

I1 = W/KS ω2 = 5.17/.05x150

2

I2 = mk2 = 500 x (42.875x10

-3 )

2

= 0.9191kg.m2

Actual Inertia of Moment If

If = I1 –I2

= 3.6764kg.m2

∆E = If x Cs x ω2

= 3.6764 x 0.04 x (150)2

= 3308.76 kg m

2 /s

2

Power, P = 2πNT/60

P=13.4HP=13.4x0.746=9.991KW

T=Px60/(2πN)=9.991x60/(2x3.14x1440)=0.0662N-m

Angular acceleration,

α= T/I=0.0662/3.6764=0.0180 rad/sec2

Moment,

M=If xω

=3.6764x150=551.46 N-m

MODELLING AND ANALYSIS OF FLYWHEEL

i. Modelling

A flywheel model of FISCHER PUNCHING

POWER MACHINE is created initially in ANSYS

classic software. Then optimized flywheels are

constructed in Pro-E Modelling.

ii. Analysis and Optimization:

Analysis: Structural analysis (FEA analysis) of

flywheel is done in ANSYS software

The stresses and total deformation is shown in this

software.

Optimization: Optimization is done with the help of

application software of FINITE ELEMENT METHOD

(i.e. ANSYS) and Pro-E.

AN APPROACH TO FIND OUT DEFLECTIONS

AND STRESSES IN FLYWHEEL:

In advent of the above discussion the present work is

planned, which is basically focus on an estimation of

deflections and von-mises stresses at different loading

conditions for four different working stages. This is

done as follows:


410

a) MODELING OF SOLID DISC TYPE

FLYWHEEL:

Initially a CAD model of the solid disc type

flywheel was created using the software ANSYS

classic.

b) FINITE ELEMENT MODELING USING ANSYS

11:

Geometry derived from the ANSYS classic model was

used to construct the finite element model. The purpose

of a finite element analysis is to recreate mathematically

the behavior of an actual engineering system. In other

words, the analysis must be an accurate mathematical

model of a physical prototype. This model comprises

all the nodes, elements, material properties, real

constants, boundary conditions, and other features

that are used to represent the physical system.

Model generation means generating the nodes and

elements that represent the spatial volume and

connectivity of the actual system, and defining the

geometric configuration of the model’s nodes and

elements.

c) Structural Analysis (Solid Flywheel):

The analysis was conducted under the effects of

different condition of loads,at four working stages viz.

motionless, starting, speed changing and constant speed.

The analysis consist of pre-processor, solver and post-

processor. Input parameters like boundary conditions,

element type, material properties are entered, then after

creating model solver reads the data defined by pre-

processor and then stresses are evaluated in post-

processor.

MODELLING OF EXISTING FLYWHEELOF

PUNCHING PRESS

FSTRUCTURAL ANALYSIS OF SOLID

FLYWHEEL

Structural analysis comprises a set of physical laws and

mathematics required to study and predicts the behavior

of structures. It includes the following methods:

Analytical methods

Strength of materials methods

Elastic methods

Finite element methods

Variation in Displacement


411

Variation in Von-Mises Stress

Table1. Analysis and Result for solid flywheel

Stage Loads Von Mises

Stress (Pa)

Maximum

Deflection

(m)

stage-1 Acel_y =9.80

m/s2

194069 0.00244


m/s2

MZ =551.46

Nm

Omega_z =

0.0180 rad/s2

0.298e8 0.331745

stage-3

Acel_y =9.80

m/s2

MZ =551.46

Nm

Domega_z=

0.0180 rad/s2

Omega_z =150

rad/s

0.299e8 0.331729


m/s2

Omega_z= 25

rad/s

0.981e7 0.027952


412

STRUCTURAL ANALYSIS OF WEB FLYWHEEL

When web is created in the flywheel (i.e. somewhat

material is reduced) mass of flywheel reduces.

Now, Mass of flywheel=430kg

Drive Force

Fd = m x a = 430 x 964.68 = 414.812 KN

Specific Weight Density

W = (r/4)x482.34 = 42.875x10-3

x 414.812/4

= 4.44627KN-m

I1 = W/KS ω2 = 4.44627/.05x150

2 =3.9522 kg-m

2

And, I2 = 430(42.875x10-3

)2

=0.79045kg-m2

If = 3.9522-0.79045 = 3.16179kg-m2

∆E=I x C S x ω2 = 3.16179 x 0.04(150)

2 = 2845.5kg-m

2

/s2

Table 2. Combinations of loads(web flywheel)

Working Stage Combination of loads

Motionless (stage-1) Gravity

Starting (stage-2) Gravity + MZ + Domega_z

Speed Changing

(stage-3)

Gravity + MZ + Domega_z +

Omega_z

Constant speed

(stage4)

Gravity + Omega_z

Structural Analysis of web flywheel is done using

following steps:-

a) Importing the iges file from PRO-E to ANSYS.

b) Clicking on solution ,then define loads ,then delete

,then all load data and press enter

c) Applying the displacement through structural.

d) Applying gravity, inertia, and angular acceleration,

inertia and angular velocity, and moment from

structural.

e) Then press the solve.

f) Repeating the general post-processor for getting the

output.

Variation in Displacement

Figure 1. Displacement stage –I

Figure 2. displacement stage –II

Figure 3. displacement stage –III

Figure 4. Displacement stage –IV


413

Figure 5. von mises stress stage –I

Figure 6. von mises stress stage –II

Figure 7. von misses stress stage –III

Figure 8. von mises stress stage –IV

Analysis and Result for web flywheel:-

Table 3. Analysis of web flywheel


Stress

(Pa)

Maximum

Deflection

(m)


m/s2

0.212e9 0.001606

stage-2

Acel_y =9.80

m/s2

MZ =551.46

Nm

Domega_z=

0.0180 rad/s2

0.515e9 0.004003

stage-3

Acel_y =9.80

m/s2

MZ =551.46

Nm

Domega_z=

0.0180 rad/s2

Omega_z

=150 rad/s

0.122e10 0.025801


m/s2

Omega_z= 25

rad/s

0.121e10 0.027930

Comments: - The deflection at all the four stages,

especially stage-1 and stage-2, has been decreased

obviously. It shows that there is change of design

parameters with respect to change in mass of flywheel.

STRUCTURAL ANALYSIS OF WEB FLYWHEEL

WITH HOLE

Improvement

Tentatively, four sectional blocks are cut from the

flywheel . Then mass of flywheel reduced again,

Now, Mass of flywheel=380kg

Drive force,

Fd = m x a = 380 x 964.68 = 366.5784 KN


414

Specific weight density, W = (r/4)x366.578 =

42.875x10-3

x 366.578/4

= 3.929KN-m

I1 = W/KS ω2 = 3.929/.05x150

2 =3.4927

So,I2 =380(42.875x10-3

)2

=0.698kg-m2

If =3.4927-0.698=2.79kg-m2

∆E=I.C S. ω2 =2.79x.04(150)

2 =2515.2kg-m

2 /s

2

Web flywheel with hole

Table 4. Combinations of loads

Working Stage Combination of loads

Motionless (stage-1) Gravity

Starting (stage-2) Gravity + MZ + Domega_z

Speed Changing (stage-

3)

Gravity + MZ + Domega_z +

Omega_z

Constant speed (stage4) Gravity + Omega_z

Structural Analysis of web flywheel with holes is

done using following steps:-Similar analysis will be

done on four sectional blocks cut in flywheel as done

previously in solid flywheel and web flywheel.

Figure 9. displacement stage –I

Figure 10. displacement stage –II

Figure 11. displacement stage –III

Figure 12. displacement stage –IV

Figure 13. von mises stress stage –I

Figure 14. von mises stress stage –II

Figure 15. von mises stress stage –III


415

Figure 16. von mises stress stage –IV

Analysis and Result for web with hole flywheel:-

Table 5. Analysis of web with hole flywheel


Stress

(Pa)

Maximum

Deflection (m)

stage-1 Acel_y =9.80 m/s2 0.346e9 0.001731

stage-2 Acel_y =9.80 m/s2

MZ =551.46 Nm

Domega_z=

0.0180 rad/s2

0.640e9 0.004225


MZ =551.46 Nm

Domega_z=

0.0180 rad/s2

Omega_z =150

rad/s

0.115e10 0.026788


Omega_z= 25

rad/s

0.112e10 0.028902

Comments:- The deflection at all the four stages, especially

stage-1 and stage-2, has been decreased obviously. Similarly,

it shows that there is change of design parameters with respect

to change in mass of flywheel. And there is less effect on

energy fluctuations.

III. RESULTS AND DISCUSSION

This chapter deals with the comparison of results

obtained by Ansys software . Thus the results are

comparing the fluctuation of energy and moment of

inertia with respect to the reduction in mass of flywheel.

Also, deflections and von-Mises stresses obtained by

Ansys software are compared for all four stages with

different modificated flywheel. The heavy flywheel is

considered and modified for reducing the fluctuations of

energy .

In this project all the modifications done in existing

flywheel are designed and modelled with dimensions

in the Pro-E software.

In the Pro-E software after modeling, it has been

analyzed in ANSYS software for deflection and von-

misses stresses for all modifications in flywheel.

A static structural analysis determines the

displacements, stresses, strains, and forces in

structures or components caused by loads that

includes inertia and don’t include vibrations.

The deflection at all the four stages, especially stage-

1 and stage-2, has been decreased in case of web

flywheel.

The deflection at all the four stages, especially stage-

1 and stage-2, has been decreased obviously.

Similarly, it shows that there is change of design

parameters with respect to change in mass of

flywheel. And there is less effect on energy

fluctuations.

Table 6. Comparison of Results

TYPE OF

FLYWHE

EL

MASS OF

FLYWHE

EL

MOMEN

T

OFINERT

IA

FLUCTUAT

ION OF

ENERGY

SOLID

FLYWHE

EL

500 3.67kg-m2

3308.76kg-

m2 /s

2

FLYWHE

EL WITH

WEB

430 3.16kg-m2

2845.5kg-m2

/s2

FLYWHE

EL WITH

WEB

WITH

HOLE

380 2.79kg-m2

2515.2kg-m2

/s2

Table 7. Comparison of Results of Deflection and Von-

Misses Stresses

Type of

flywheel Stage

Maximum

deflection(m)

Von-misses

stresses

(Pa)

Solid

flywheel stage-1 0.00244 194069


416

stage-2

stage-3

stage-4

o.3317

0.3317

0.0279

0.298e8

0.299e8

0.981e7

Flywheel

with web

stage-1

stage-2

stage-3

stage-4

0.001606

0.004003

0.025801

0.027930

0.212e9

0.515e9

0.122e10

0.122e10

Flywheel

with web

with hole

stage-1

stage-2

stage-3

stage-4

0.001731

0.004225

0.026788

0.028902

0.346e9

0.640e9

0.115e10

0.112e10

IV. CONCLUSION

Based on the above design and analysis, the following

conclusions can be drawn:

There are rotational deformations due to the torsion

effect of the drive moment MZ and the inertia moment

caused by the angular acceleration (α). The maximum

stress occurs on the hub and near shaft-hole surface at

the stage-2 and stage 3, however the maximum

deflection is along the right outer-edge of the rim at the

stage-3. Compared to the situations of stress and

deflection at stage-2 and stage-3, those at stage-1 and

stage-4 are much better. Some efforts should be done to

improve the design and thus reduce the stress on the hub.

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Documents

Themed Section: Science and Technology Design and Analysis